<h1>Molecular biology</h1>
<p>Molecular biology is a branch within biology that treats the relationship between molecular behavior and cell behavior. A molecule is a structure of multiple atoms, like water (H2O) or blood sugar (C6H12O6). Cells are the basic building blocks of all organisms, both animal and plants. An animal with the weight 70 kg consists of around 50 to 100 trillion cells! (1 trillion = 1 000 000 000 000)</p>
<img>minigame_botany_water_molecule:Figure 1. A water molecule (H2O)</img>
<h2>Cells</h2>
<p>All known living organisms consist of cells. The properties of the cells can however be totally different. Plant cells may for instance use solar energy, water and carbon dioxide (CO2) to produce blood sugar and oxygen (O2). Animal cells may in contrast consume oxygen and blood sugar to produce carbon dioxide and mechanical energy. Even for two animals or plants of the same species the properties may differ slightly. When looking at your friends or even your family members you may notice that your hair or eye color is different. This is due to the differences in the cells.</p>
<p>Cells are using genetic code (called DNA) to function. It controls the cells behavior, how they produce chemical compounds and how they should replicate. Cells can be replicated by two molecular processes meiosis and mitosis. Meiosis is when two parents merge two of their cells into an offspring cell. Mitosis is the process when cells are replicated within a single organism.</p>
<h2>Chromosomes and DNA</h2>
<p>A chromosome is a compact coil of DNA (deoxyribonucleic acid). Chromosomes can be found within each living cell (animals as well as plants). The DNA contained within the chromosome works like a blueprint for the cell. It is mainly used to produce proteins for the host organism, which is an essential process for the host. If the DNA structure (called double helix) is damaged or contains undesired parts it may produce strange (or none) proteins for the host. This may lead to diseases or uncontrolled replication of damaged cells, also known as cancer. The DNA structure can be damaged by anything from high energy exposure to toxic intake.</p>
<i>Figure 1. http://openclipart.org/detail/174762/water-molecule-by-nunopequito-174762</i>